Today is the first day of ObamaCare. Specifically, it's the day that the Affordable Care Act's new health insurance exchanges are open for business.

Yes, despite the drama over the government shutdown, the exchanges will remain open. And yes, despite what you may have heard about the death of democracy, ObamaCare will mainly involve Americans going online and picking a plan from a menu of health care options provided by private insurance companies.

So, provided that the world isn't about to be engulfed in flames, here is a guide to what you need to know about ObamaCare.

What if I already have employer-based health insurance?The health insurance exchanges don't affect you. This also applies to people on Medicaid and Medicare. Feel free to go about your business.

If you don't like the current health care plan you get through work, you may be able to switch to a new one under ObamaCare, although you certainly don't have to.

Your health plan could see a few small changes. Starting in 2014, your insurance company will be required to provide cost-free coverage for certain preventative services like mammograms and flu shots, and won't be able to put a lifetime cap on your health care spending. Your insurance company also may send you rebates; under ObamaCare, insurance companies must spend at least 80 percent of the premiums they receive on health care, with any excess going back into the pockets of consumers.

What if I am self-employed and currently buy my own insurance?If the insurance you have already have meets all of ObamaCare's requirements, you can keep it. You might, however, be able to get a cheaper plan though the exchanges. Subsidies are available for people who make between the federal poverty line ($23,550 for a family of four) and four times that amount.

The Kaiser Family Foundation whipped up a handy tool to help you estimate the size of your subsidy:

Will I be eligible for the newly expanded Medicaid?If you make less than 133 percent of the federal poverty line, you may be eligible for Medicaid under ObamaCare, provided that you live in a state that has accepted a federal expansion of the program. So far, 25 states — including Texas, South Carolina, Mississippi, and Alabama — have refused, leaving people who otherwise would have qualified out of luck.

When should I sign up?There's not a huge rush. Insurance policies bought through the insurance exchanges won't kick in until Jan. 1, 2014. It might even be wise to wait a few weeks to make sure kinks have been ironed out of the system.

When do I need to purchase insurance by?The deadline to purchase insurance to escape getting hit with a tax penalty — the enforcement mechanism of the so-called individual mandate — is March 31, 2014. After that, you will be only be able to buy insurance through the exchanges if you lose your job, have a kid, get married, or get divorced, at least until the next enrollment period opens.

The tax penalty is relatively small in 2014, with a minimum assessment of $95 or 1 percent of your income, whichever is higher. That will grow to $325 the next year and $695 the year after that.

How do I pick my plan?Go to HealthCare.gov, which will point you to your state-level exchange. Some are ready to go, while others, like in Oregon, will make people go through an insurance agent or a community group until later this month. In Colorado, people will have to call a customer service line to pick their insurance plan.

The federal government, which is running more than 30 of the state exchanges, probably won't have everything figured out either. Hence the above suggestion to wait a few weeks after the exchanges go live to buy your insurance.

What will ObamaCare cover?Every insurance plan offered through the exchanges has to cover hospitalization, preventative services, prescription drugs, and other essential health benefits.

After that, you can choose from four levels of coverage: Bronze, silver, gold, and platinum, which are expected to cover 60, 70, 80, and 90 percent of the average person's out-of-pocket costs, respectively.

More comprehensive plans will, unsurprisingly, cost more. Your monthly premiums will depend on what plan you choose and what state you live in.

Is signing up going to be a total pain?Possibly. Back in March, conservatives raised a ruckus after the Associated Press got its hands on 15-page application for ObamaCare. The federal government says it should take some people only seven minutes to buy coverage, although there is no way to verify that until the health insurance exchanges open. What we do know is that you will have to provide information like your age, income, family size, and whether or not you are a smoker.